Refer to the histogram. This is an issue that you will probably run into several times and there is no guarantee that whatever you do makes your picture look perfectly exposed on everyone's device.

That said, there are some universal pointers:

• When you first bring up a picture in the raw converter, the histogram has two triangles: top right and top left. Click each one of these to activate a clipping highlighter (there's probably a proper name for this, but I don't know it). Anything that is either too bright or too dark will be highlighted. If you're not using the raw converter, you can still bring up a histogram in the regular PS view to see if some of it is going over the edge.
• Use the exposure adjustment/slider to get most of the histogram away from the right or left edge. You can also use the Shadow and Highlight sliders in the raw converter to move each individual side away from the edge.
• Let's say you're taking some low light pictures and they look fine on your LCD ... this doesn't necessarily mean they are exposed correctly. A good rule of thumb is to have most of the histogram to the right of the center. They might seem a little overexposed if your LCD is set to maximum brightness, but once you get to your editing software you'll be better off.
• Most people have their phones and monitors cranked up to be as bright as possible. If you want to print your pictures, you'll need to turn your computer screen down a bit to get a better view of how they'll look on paper. The specific brightness depends on the monitor so you may want to search your model or do some trial & error.
• Some styles intentionally overexpose. If you're going for this, then feel free to clip some of the highlighted areas.
• Something that helped me with this was showing my pictures to a professional and letting them adjust the brightness on my phone. Someone with lots of experience might be able to tell you if you photos need an exposure adjustment.

Sorry to say that there isn't a standard fix. Kind of the way it is with art ... there's no formula for the standard "good picture!" Best of luck.